预览加载中，请您耐心等待几秒...

MOSFET热阻测试.doc

预览
1/6
2/6
3/6
4/6
5/6
6/6

在线预览结束，喜欢就下载吧，查找使用更方便

下载提示 文本预览

如果您无法下载资料，请参考说明：

1、部分资料下载需要金币，请确保您的账户上有足够的金币

2、已购买过的文档，再次下载不重复扣费

3、资料包下载后请先用软件解压，在使用对应软件打开

Tony.he158-2079-5808 MeasurementofMOSFETdevicesbyboosterdevice MOSFETdevicescanbemeasuredusingthreedifferentelectricalsetups. Reversediodemeasurement Inthefirstsetupweusethereversediodeofthedeviceforheatingandmeasurementalso.ThepowerstepisappliedusingthesocalledcurrentstepmethodbyswitchingfromahigherIforce+IsensecurrentleveltoIsensemeasurementcurrentandusingtheforwardvoltageastemperaturesensitiveparameter. toT3Sterchannel Isense Iforce BothIforceandIsensecanbeprogrammedintheboosterwhichisaunipolardeviceofpositivepolarity.Thedevicevoltageistypicallybelow1V. MOSdiodemeasurement InthesecondsetupweconnecttheGatetotheDrainpinandmeasurethisthreeterminaldeviceasasocalledMOSdiode.WeapplyasimilarcurrentstepasdescribedaboveandmeasuretheforwardvoltageoftheMOSdiode. toT3Sterchannel Isense Iforce Thedevicevoltageistypically2..5Vcorrespondingtogatethresholdvoltage. Measurementwithheatingonchannelresistanceandsensingonreversediode Inthisthirdsetuptheelectricalconnectionisabitmorecomplex. toT3Sterchannel Isense Iforce UG IntheheatingphasetheUGvoltageisathighlevelensuringcontinuousheatingcurrentthroughthechannelresistanceRDSon.Thepositiveheatingcurrentcomesfromtheboosterandanegativesensecurrentisgeneratedbyanotherequipment,e.g.T3Ster. AtthestartofthecoolingIforceisswitchedoffandUGalsogoestozerothusclosingthetransistor.ThecontinuouslyflowingnegativeIsensecausesthereversediodetoopen. Thedevicevoltageistypicallylowonthechannelresistanceand-0.5Vonthereversediodeatcooling. Apracticalproblemisthattheboosteroutputisofdevicesoflargesurfaceinordertoswitchhundredamperes.Thiscancauseleakageatnegativevoltages,resultinginlossofthemeasurementcurrentfromexternalsourceandnoiseinthemeasurement. Asimple“tandem”circuitrycanstopthisleakagewhilewithstandingthecurrentlevelsofthemeasurement. toT3Sterchannel Isense Iforce UG T1 T2 DUT T1andT2aretransistorsofthesametypeandcharacteristics. T1isthedeviceundertest.T2behavesasacontrolswitchwhichisONduringheatingbutOFFduringcoolingsuchisola